Kelie C Yoho, Samuel DeGrey, Doris Lagos-Kutz, Erik J Wenninger
Potato virus Y (PVY) is an aphid-transmitted pathogen that severely limits global potato production, especially in seed potato systems. Understanding the phenology and relative abundance of different aphid vector species should clarify seasonal PVY risk and allow optimization of timing of appropriate management tactics. This study aimed to characterize seasonal patterns of alate aphid activity in Idaho seed potato fields. Data were collected over 5 yr (2015, 2016, 2019, 2020, and 2021) using bucket traps to monitor alate aphid movement. Generalized additive mixed models were used to analyze the relationship between aphid abundance and environmental factors such as growing degree days (GDDs) and precipitation. The models identified 3-key peaks in aphid abundance, with the largest peak occurring early in the season, coinciding with potato emergence and, therefore, presenting the highest risk of PVY infection. Pemphigus spp. were the largest contributors to this early season peak. Multiple species contributed to the mid-season peak, including Acyrthosiphon lactucae, Hayhurstia atriplicis, and Lipaphis pseudobrassicae, that likely dispersed from weedy hosts, suggesting weed control could be a practical approach to reducing vector abundance during the growing season. Other captured taxa, including Acyrthosiphon spp. and Metopolophium dirhodum, suggest surrounding cultivated hosts contribute to vector pressure. The findings indicate that while GDD models can help guide the timing of protective measures such as mineral oil applications, closely monitoring the condition of surrounding vector host plants, such as alfalfa, cereals, and weeds, may also be critical for making informed management decisions.